Method of producing grained-rubber articles



March 20, 1928. 1,663,275

T. J. MELL METHOD OF PRODUCING GRAINED RUBBER ARTICLES Filed Nov. 18. 1926 I JUL E7770]? 727a J-/ 7E// Patented Mar. 20, 1928.

UNITED STATES PATENT OFFICE.

Ton J. MELL, or AKRON, onro, xssrenon ro THE B. F. eoonnrcn COMPANY, or new YORK, N. Y., A- CORPORATION OF NEW YORK.

METHOD OF PRODUCING GRAINED-BUBBER ARTICLES Application filed November 18, 1926. Serial No. 149,149.

This invention relates to the art of producing variegated rubber articles and especially rubber articles having a wood-grain effect in their surface color design. Various expedients have been proposed heretofore for obtaining such effects in rubber or other initially plastic material, but the procedures,

proposed have been elaborate and expensive and the results inferior as compared with my invention, wherein the actual structural characteristics of wood is closely approximated, so that difl'erent graining effects may be obtained from the grained mass of rubber by cutting it in accordance with the plan of sawing which is employed to obtain a like grain efiectin wood.

My chief objects are to provide an improved grained article of rubber in close imitation of-the natural grain of wood, and

rovide an inexpensive method of produclng such an article.

In attaining these objects I produce a slab of rubber compounds of different colors in which the compounds have a structural relation closely approximating that of the differently colored portions of wood, and I have discovered that this can be done effectively and inexpensively by passing the differently colored rubber compounds simultaneously through an ordinary extruding machine, the compounds preferably being fed into the machine in such manner and inslabs of such form "as to avoid an excessive intermixing of them b the screw of the extruding machine, and in such association as to be worked into the desired grained struc-- ture by the screw.-

, Of the accom anyingdrawings:

Fig. 1.is a si e elevation of apparatus, into eluding an extruding machine, for forming and handling the slab of rubber.

Fig. 2 is a cross-section of a vulcanizing press havin a plurality of the slabs mounted therein or vulcanization.

Fig. 3 is a perspective view of apparatus for cutting the slab into sheets, and of the work in association therewith.

Referring to the drawings, machine, 10, is preferably provided with a die adapted to form a rubber strip 11 of rectangular cross-sectional form, and means,

such as'the endless-belt conveyor 13, having driving connection with the extruding ma chine 10 through a variable speed device '14,

the extruding is provided for receiving the continuous slab strip as it is formed.

The stocks of different colors are preferably formed into respective strips 15, 16 of -so' that they will to a considerable extent maintain a layer-on-layer relation throughout their passage through the machine. My invention is not wholly limited to this relation of the stocks as they pass into the machine, however, as the manner of feeding them into the machine may be varied in accordance with the type of graining desired.

The continuous slab strip 11 preferably is cut into lengths 11, 11 upon the conas shown in Fig. 1, and fed into the veyor 13 and each of these lengths is sliced into a plurality of sheets by apparatus such as that shown in Fig. 3, in accordance with my United States Patent No. 1,588,797, of

June 15,1926, the apparatus comprising a pair of driven feed rolls 17 18 adapted to compress and drive forward the slab and an endless belt-knife 19 adapted to slice the slab as itemerges from the nip of the rolls, the rolls preferably being so closely set as to create in the slab a zone of substantial tension, in the direction of its thickness,

along the compression zone,and the knife being so positioned as to cut in such region of tension.

The slab is preferably vulcanized before the slicing operation, as by mounting a plu-" rality of the slabs in a vulcanizing press such as that shown at 21, with metal retaining strips 22 mounted between the slabs and at the outer edges of the' outermost slabs.

The slicing o the slab exposes its internal structure as a surface design, and this design, by reason of the somewhat but not entirely uniform action of the extruding machine screw upon the stocks, very closely approximates the appearance of wood grain, especially when the differently colored slabs are fed into the machine superposed, elongated strips as described. The vulcanization of the slabs before the slicing operation avoids distortion and smearing of the design in the slicing of the slab.

Modifications are possible within the scope of my invention as defined in the appended claims.

I claim: 2. A method as defined in claim 1 in which 1. The method of producing a grained the compounds are fed into the extruding l0 rubber article which comprises passing two machine in the form of elongated strips with rubber compounds of different colors a strip of one color extendlng alongside of F through an extruding machine together to a strip of another color.

produce an internally grained strip and re- In Witness whereof I have hereunto set moving rubber from the strip to expose the my hand this 11th day of November, .1926. internal grain thereof. TOD J. MELL. 

